1. Field of the Invention
The present invention relates to pyrene compounds and organic electroluminescent devices using the same. More specifically, the present invention relates to blue light emitting pyrene compounds with high color purity and long lifetime, and organic electroluminescent devices using the pyrene compounds.
2. Description of the Related Art
As displays have become larger in size in recent years, there has been an increasing demand for flat panel display devices that take up little space. Liquid crystal display devices as typical flat panel display devices can be reduced in weight when compared to the prior art cathode ray tubes (CRTs), but have disadvantages in that the viewing angle is limited, the use of backlight is inevitably required, etc. Organic light-emitting diodes, (OLEDs) as a new type of flat panel display devices are self-luminous display devices. Organic light-emitting diodes have the advantages of large viewing angle, light weight, small thickness, small size and short response time over liquid crystal display devices. Based on these advantages, the applicability of organic light-emitting diodes to full-color displays or lighting systems is expected. Under these circumstances, there is a growing need for blue light emitting materials with high luminance, high efficiency and high color purity.
U.S. Pat. No. 7,053,255 discloses a blue light emitting compound which has a diphenylanthracene structure at the center and a specific structure substituted with an aryl group at end portions, and an organic electroluminescence device using the blue light-emitting compound. This organic electroluminescent device has the drawbacks of insufficient efficiency of light emission and low luminance.
Further, U.S. Pat. No. 7,233,019 and Korean Unexamined Patent Publication No. 2006-0006760 disclose organic electroluminescent devices using substituted pyrene compounds. The devices have poor color purity of blue light, which makes it difficult to achieve deep blue light emission. Accordingly, there is a limitation in manufacturing displays providing a full range of natural colors.